Wet season securing island fruit (7)
I believe the answer is:
raisins
'fruit' is the definition.
(I've seen this before)
'wet season securing island' is the wordplay.
'wet season' becomes 'rains' (I've seen this in another clue).
'securing' is an insertion indicator.
'island' becomes 'is' (geographical abbreviation).
'rains' placed around 'is' is 'RAISINS'.
(Other definitions for raisins that I've seen before include "Fruit that's dried" , "Dried grapes used in cakes" , "Dried grapes, nice in cakes" .)